fn main() {
    let s2 = String::from("bbb");
    let (s3, len) = calc_length(s2);
    println!("in main: the length of '{}' is {}", s3, len);
}

fn calc_length(s: String) -> (String, usize) {
    println!("receive: {}", s);
    let length = s.len();
    (s, length)
}
